The best writers make it look easy. Not just that, they make it seem as though the words just flowed out of them. We know that that is not, can not, be true. Even the fastest writers are masters of control. Their speed is in part the result of careful planning and diligent editing as they go.
In her classic The Writing Life, the great Annie Dillard put it thus:
Putting a book together is interesting and exhilarating. It is sufficiently difficult and complex that it engages all your intelligence. It is life at its most free. Your freedom as a writer is not freedom of expression in the sense of wild blurting; you may not let rip. It is life at its most free, if you are fortunate enough to be able to try it, because you select your materials, invent your task, and pace yourself…
Most people focus on her command, “You may not let rip.” For good reason. Letting rip often just means a loss of control. It may feel good in the moment, but your readers will notice.
Follow Dillard. When writing, freedom means giving vent to your inner voice. It also paying close attention to everything you put down on a page. That way, your voice will have a voice.